Science_Form_3

Chapter 8: Radioactivity

Cosmic Rays

Cosmic rays are
high-energy radiation
produced outside the
Solar System or from
another galaxy. These
cosmic rays are also
known as galactic
cosmic rays.

Photograph 8.1 Cherenkov telescope on Mount Hopkins, United States of
America used to detect cosmic rays

Background Radiation

Background radiation is made up of various types of ionising radiation in the environment.
Background radiation is released from various sources including natural sources and man-made
sources. Sources of background radiation include:
• cosmic rays
• radioactive radiation from natural radioactive substances in the surroundings
• radioactive wastes from nuclear accidents and nuclear tests
• radioisotopes from medical use

Unit of Dose Rate Measurement for Background Radiation

Ionising radiation that is absorbed into the human body will damage body cells. Due to

this, the biological effect from ionising radiation on human body is measured in a quantity

known as dose. A dose of 1 Sv is equivalent to 1 joule of BRAIN
ionising radiation energy that is absorbed by 1 kilogram of TEASER
living tissue. The unit of background radiation dose that is
commonly used is microSievert/hour (μSv/h). What is the meaning of 1 μSv/h?

(a) In the garden (b) In the school compound

Photograph 8.2 Measuring background radiation using a Geiger counter

Study and compare the readings of the dose rate of background radiation on a Geiger Counter
in Photograph 8.2. What is the unit of dose rate measurement for background radiation shown
in the readings on the counter?

8.3.3 243

Safe Background Radiation Dose in Daily Life

Background radiation SCIENCE INFO Websites
or ionising radiation
Exposure to radiation in daily life
dose of less than Safe level of background radiation
0.2 μSv/h is the dose is: http://links.and l17.com/BT_
normal level or • < 0.2 μSv/h Science_244_2 and click
“Radiation Level“
safe level. Based on • < 0.0002 mSv/h

Photograph 8.2, the • < 1 752 μSv/year
garden and school • < 1.752 mSv/year

compound are safe

areas because both areas have background radiation dose of

less than 0.2 μSv/h.

The estimation of dose rate of ionising radiation from

various sources in daily life are shown in Figure 8.11.

Identify which sources are safe for an individual.

Outer space: TV/computer: X-ray
cosmic rays ionising radiation 5.5 mSv/medical
0.35 mSv/year 0.01 mSv/h test

High altitude: Smoking:
cosmic rays radioactive
0.3 - 0.5 mSv/year radiation
55 mSv/cigarette

Flight: Building:
cosmic rays radioactive radiation
0.003 mSv/h 1.5 mSv/year

Environment: Food: radioactive
background radiation radiation
0.4 – 1.0 mSv/year 0.1 – 0.5 mSv/year

Figure 8.11 Estimation of dose rate of ionising radiation
244 8.3.3

Chapter 8: Radioactivity

Risks from Exposure to Natural Ionising Radiation

Absorption of ionising radiation by the human body imposes health risks which are affected by
the dose of ionising radiation received. Several actions can be taken so that the ionising radiation
dose received does not exceed the safe level for the human body as shown in Table 8.5.

Table 8.5 Among the safety measures that need to be taken so that SCIENCE INFO
the ionising radiation dose received does not exceed the safe level
for the human body Marie and Irene Curie are the
only mother and daughter to
Source of Safety measures have received three Nobel Prizes.
ionising radiation Marie Curie received two Nobel
Use appropriate protective equipment Prizes, which are Nobel Prize in
dose received such as spectacles fitted with anti- Physics in 1903 and Nobel Prize
Background ultraviolet film, anti-ultraviolet umbrellas in Chemistry in 1911. Irene Curie,
radiation and others Marie Curie’s daughter, received
her Noble Prize in Chemistry in
Taking X-ray X-ray taken with doctor’s prescription 1935. Without realising the risks
Television of being exposed to ionising
Ensure the distance between the radiation, they died of cancer
Food contaminated television and the viewer is at least caused by excessive exposure to
with radioactive 2 m. gamma rays during their research.
substances
Do not eat food produced in areas
Cosmic rays contaminated with radioactive
substances such as fish from the
sea contaminated with radioactive
substances.

Working hours of a pilot are limited to
a certain period of time because the
pilot is exposed to cosmic rays.

Activity 8.4

To interpret data on health risks related to the absorption level of • ICS
ionising radiation by the human body
• Simulation
Instructions
activity

1. Work in groups.
2. Gather information from various sources on the health risks related to the absorption
level of ionising radiation by the human body.
3. Discuss the health risks to the human body due to absorption of the following doses
of ionising radiation in a year.
(a) Doses of 10 Sv.
(b) Doses in the range of 1 Sv to 10 Sv.
(c) Doses in the range of 0.1 Sv to 1 Sv.
(d) Doses of less than 0.1 Sv.
4. Share the outcome of your group discussion in class.

8.3.4 245

Examples of Absorption of Ionising Websites
Radiation Exceeding the Safe Level and
Safety Measures that Need to be Taken Safety measures for airline crew
members who are exposed to
As most cosmic rays are absorbed by the atmosphere, the cosmic rays.
dose of cosmic rays on the surface of Earth is normally at
a value of less than 0.2 μSv/h, which is a normal or safe http://links.and l17.com/BT_
level. The higher a person is from the surface of Earth, the Science_246
stronger the cosmic rays he receives. Name an example of a
career that involves working at high altitudes.

Airline crew members such as
pilots (Photograph 8.3), stewards and
stewardesses normally receive cosmic
ray doses exceeding the safety level.
They are exposed to strong cosmic
rays in flights at high altitudes. Due
to this, their working hours in the sky
are limited to a certain period of time.

Photograph 8.3 Pilots

Formative Practice 8.3

1. (a) What is ionising radiation? Give one example of ionising radiation.
(b) What is non-ionising radiation? Give one example of non-ionising radiation.

2. Underline the correct answers.
(a) The ionising power of beta radiation is (higher/lower) than the ionising power of alpha
radiation but (higher/lower) than the ionising power of gamma ray.
(b) The penetration power of beta radiation is (higher/lower) than the penetration power
of alpha radiation but (higher/lower) than the penetration power of gamma ray.

3. (a) State two natural sources of ionising radiation.
(b) State three man-made sources of ionising radiation.

4. (a) State the unit of dose rate measurement for background radiation.
(b) What is 1 sievert (Sv)?
(c) What is considered a safe level of background radiation dose?

5. Why does the absorption level of ionising radiation for an individual working in the
aviation sector normally exceed the safety level?

6. A student watches television for 2 hours every day. Calculate the dose rate of ionising
radiation received by the student after 5 days. (Dose rate of ionising radiation from television
= 0.01 mSv/h)

246 8.3.4

Chapter 8: Radioactivity

8.4 Uses of Radioactive Radiation

Radioactive Radiation in Daily Life

Radioactive radiation such as alpha radiation (α), beta radiation (β) and gamma ray (γ) are used
in various fields in daily life as follows:

Archeology and geochronology Photograph 8.4 Dinosaur bones
Carbon dioxide in the air is made up of carbon-12
(C-12) which is stable and carbon-14 (C-14) which
is radioactive. As carbon dioxide is absorbed and
released by the body of living organisms, the
percentage of C-14 in the tissues of the organisms
does not change.

As soon as the organisms die, the amount of
C-14 in their tissues begins to decline because they
decay by emitting beta radiation with a half-life,
T 1 , of 5 700 years. By measuring the activity of

2

C-14, the age of the remains can be determined.
This method is known as carbon-14 dating and
is used by archeologists or geochronologists to
determine the age of fossil and artifacts.

Monitoring the thickness of metal sheets
(Industry)
A thickness control device monitors the thickness of
metal sheets in factories. A metal sheet is passed in
between a beta radiation source and a beta radiation
detector. If the beta radiation detector detects too
much beta radiations, this means that the metal
sheet is too thin.

Photograph 8.5 Monitoring the
thickness of metal sheets

Agriculture Figure 8.12 Determining the absorption
In agriculture, the rate at which beta radiation is rate of phosphorus-32 (P-32) fertiliser
emitted during the nuclei decay of phosphorus-32
(P-32) is used to determine the absorption rate 247
of phosphate fertiliser in plants. Radioactive
radiation is also used to kill beetles, control the
population of pests by sterilisation, determine the
best type of phosphate fertiliser, and modify the
characteristics of plants.

8.4.1

Defence
Radioactive substances can be used in the field of defence such as the nuclear bomb. Besides
heat, radioactive radiation released from the explosion of a nuclear bomb destroys almost all
living things including humans and its effect exists for generations.

Today in history

On 20 September 2017, Malaysia
signed the ICAN agreement to ban
nuclear weapons at a United
Nations (UN) Conference.

Photograph 8.6 Atomic bomb explosion

Food preservation
The Radura logo in Figure 8.13 is used to label food preserved using radioactive radiation
such as gamma rays. Gamma rays are used in the preservation of food such as fruits to kill
bacteria in the food.

Figure 8.13 Radura logo Photograph 8.7 Preservation of food
using gamma rays

Medical
Gamma rays from caesium-137 (Cs-137) or
cobalt-60 (Co-60) are used to kill cancer cells.
Radioactive radiation is also used to determine
the location of blood clots using sodium-24
(Na-24), treat tumours in the brain using
technetium-99 (Tc-99), destroy germs using
cobalt-60 (Co-60) and treat thyroid glands using
iodine-131 (I-131).

Photograph 8.8 Gamma rays used
to treat cancer

248 8.4.1

Chapter 8: Radioactivity

Activity 8.5

To carry out a Gallery Walk on the use of radioactive radiation in • ICS
various fields • Technology-

Instructions based activity
1. Work in groups. • STEM

2. Gather information from the Internet, print media and other electronic media on the
use of radioactive radiation in the areas of agriculture, defence, medicine, archeology
or geochronology, industry and food preservation.
3. Discuss the following:
(a) Types of radioactive radiation used
(b) Ways of using radioactive radiation
(c) Careers related to the use of radioactive radiation
4. Carry out the gallery walk activity.

Safe and Proper Handling of Radioactive Substances and
Radioactive Waste

Safety measures in the handling of radioactive sources and radioactive waste are shown in
Figure 8.14.

Storing radioactive sources Radioactive substances are Robotic hands are used to
or radioactive waste in shielded with thick slabs of handle radioactive substances
containers with thick lead lead. safely.
walls.

Wearing appropriate Safety measures when Detecting the dose rate
protective clothing when handling radioactive of radioactive radiation
handling radioactive sources and absorbed into the body
substances radioactive waste with detectors such as
radiation badges.

Disposal of radioactive waste
done safely and properly

Figure 8.14 Safety measures in the handling of radioactive sources and radioactive waste 249
8.4.1 8.4.2

Appreciating the Importance of Websites
Radioactive Radiation
Handling the disposal of
The importance of radioactive radiation for the well-being radioactive waste safely and
of humans makes us grateful to the Almighty for creating properly
radioactive particles that have many uses to sustain life.
http://links.and l17.com/BT_
The first artificial radioactive element, phosphorus-30 Science_250
(P-30), was created by Irene Joliot-Curie, the daughter
of Marie Curie. Since 1934, many artificial radioactive
elements have been produced by scientists. Artificial
radioactive elements cannot be produced without the
radioactive particles.

Formative Practice 8.4

1. State one example of the use of radioactive radiation in the following fields:
(a) Archeology and geochronology
(b) Medicine
(c) Agriculture
(d) Defence
(e) Industry

2. (a) State the type of radioactive radiation used in the preservation of food.
(b) How can this type of radioactive radiation preserve food?

3. Why are radioactive sources or radioactive waste kept in boxes with thick lead walls?

4. Figure 1 shows a warning symbol.

Figure 1

(a) What is the meaning of the warning symbol shown in Figure 1?
(b) Name one example of a place or area which displays this warning symbol.
(c) Among the three types of radioactive radiations, which is the least dangerous? Explain

your answer.

5. (a) State one metal that is used to make appropriate protective clothing to handle
radioactive substances.

(b) State one advantage and one disadvantage of using the metal to make the protective
clothing mentioned in 5(a).

250 8.4.2

Summary

Radioactivity

Discovery of Decay process of unstable Applying the understanding Uses of radioactive
radioactivity nucleus by emitting of the structure of atom radiation
radioactive radiation and nucleus
Chronological order in fields such as
Examples of radioactive in the
Wilhelm Roentgen substances Agriculture, defence,
who discovered Formation of positive medicine, archeology,
X-ray (1895) C-14, Rn-222, Th-234, and negative ions geochronology,
U-238 industry, food
Henri Becquerel by preservation
who discovered units of radioactivity
radioactivity (1896) Ionising radiation Safety measures
becquerel (Bq), such as
Marie and Pierre Curie curie (Ci) r 4UPSJOH PG SFTPVSDFT
who succeeded in Alpha radiation, beta radiation, r 1SPUFDUJWF DMPUIJOH
detecting radioactivity gamma ray and X-ray r 4IJFME JO MFBE CPY
through its ionising r 6TF PG SPCPUJD
effects (1897) from
hands
r 3BEJBUJPO CBEHFT
r 4BGF BOE QSPQFS

disposal
Chapter 8: Radioactivity

251
Natural sources Man-made sources
such as cosmic such as nuclear
rays, background tests and artificial
radiation radioactive
elements

Self-reflection

After studying this chapter, you are able to:

8.1 Discovery of Radioactivity
Describe the history of the discovery of radioactivity.
Explain with examples radioactive substances, radioactivity and the concept of half-life.

8.2 Atom and Nucleus
Draw an atomic structure in a stable state.
Explain the formation of positive ions and negative ions.

8.3 Ionising Radiation and Non-ionising Radiation
Describe ionising radiation and non-ionising radiation.
Differentiate the three types of ionising radiation in radioactive decay.
Explain with examples sources of ionising radiation in the environment, natural sources
and man-made sources.
Discuss ways to manage the risks from exposure to natural and man-made
ionising radiation.

8.4 Uses of Radioactive Radiation
Communicate the use of radioactive radiation for well-being.
Justify the importance of proper handling radioactive substances and radioactive waste.

Summative Practice 8

Answer the following questions:

1. Mark ‘✓’ for the correct statements and ‘×’ for the incorrect statements.

(a) Wilhelm Roentgen discovered the X-ray. ( )
)
(b) Henri Becquerel used the element radium in his investigations on radioactivity. ( )

(c) The death of Marie Curie is caused by the exposure to gamma rays. (

2. What is the meaning of radioactive decay?

3. Name the radioactive substance in the common salt used in the medical field.

4. Pa-234 decays to U-234 by emitting beta radiation. If the half-life of Pa-234 is 5.2 hours,
what is the remaining mass of Pa-234 after 20.8 hours given its original mass is 32 g?

252

Chapter 8: Radioactivity

5. Tables 1(a) and 1(b) show the formation of ions.

Table 1(a)

Magnesium atom, Mg Magnesium ion, Mg2+

Subatomic particle Number Charge Subatomic particle Number Charge

neutron, n 12 0 neutron, n 12 0

proton, p 12 +12 loses two proton, p 12 +12
electron, e 10 –10
12 –12 electrons electron, e

The charge on magnesium 0 The charge on magnesium +2
atom, Mg ion, Mg2+

Table 1(b)

Fluorine atom, F Fluoride ion, F –

Subatomic particle Number Charge Subatomic particle Number Charge

neutron, n 10 0 neutron, n 10 0
proton, p 9 +9
electron, e 9 +9 gains one proton, p
electron 10 –10

9 –9 electron, e

The charge on fluorine atom, F 0 The charge on fluorine ion, F– –1

(a) Is the ion formed in Table 1(a) a positive ion or negative ion? Explain your answer.
(b) Is the ion formed in Table 1(b) a positive ion or negative ion? Explain your answer.

Focus on HOTS

6. (a) State three similarities between X-ray and gamma ray.
(b) Figure 1 shows the condition of two samples of strawberries, X and Y, before and after
7 days.

Day one After 7 days Day one After 7 days

Sample of strawberries X Sample of strawberries Y

Figure 1

253

(i) Which sample has been preserved? Explain your answer.
(ii) What is the radioactive radiation used to preserve food?
(iii) How can this radioactive radiation preserve food?
(iv) Is food preserved using this radioactive radiation safe to be consumed?

Explain your answer.

7. (a) Figure 2(a) shows an activity that is normally carried out in a laboratory to study
radioactive substances.

Figure 2(a)

Based on the activity in Figure 2(a), describe the safety measures taken when handling
radioactive substances.

(b) Figure 2(b) shows an example of the use Beta radiation Radiation
of beta radiation in an industry. source detector
Beta radiation is used to monitor the
volume of drink in bottles. Beta radiation Bottle of
is directed towards the passing bottle drink
as shown in Figure 2(b). If the bottle is
not filled sufficiently, the beta radiation Conveyor
will pass through the bottle and is then belt
detected by a detector. The circuit attached
to the detector then removes the bottle. Bottles removed

You are required to create a model to show Figure 2(b)
the quality control system that monitors
the volume of drink in bottles as shown in
Figure 2(b) using the materials below.

• LED
• Empty mineral water bottle
• Newspaper
• Mirror

254

THEME Earth and Space
Exploration
4

The RazakSAT-2 satellite is a satellite
created entirely by local scientists. One
of the uses of this satellite is in the field
of defence.

Our life is affected by local
weather conditions. For
example, we will use an
umbrella on a rainy day.
What is the importance of
space weather?

255

CChhaapptteerr

91 Space Weather

What is the structure of the Sun?
What phenomena occur on the surface of the Sun?
What are the effects of space weather on Earth?

Let’s study

Activities of the Sun that affect Earth
Space weather
256

Science Gallery

The Sun’s X9.3 class solar flare at 8.02 am on
6 September 2017

On 6 September 2017, coronal mass ejections caused
disturbances to telecommunication, navigation system and
electric power lines for about an hour. What are the effects of
this phenomenon on daily life on Earth?

Keywords Corona
Solar flare
Sun Sunspot
Core Solar cycle
Radiation zone Solar wind
Convection zone Magnetosphere
Photosphere Prominence
Chromosphere
Granule 257

9.1 Activities of the Sun that Affect Earth

The Sun appears as a ball of How is helium
glowing gases as shown in produced in the
Photograph 9.1. The Sun Sun?
consists almost entirely of
two types of gases, hydrogen MEI
and helium.
Convection zone
Photograph 9.1 The Sun Radiation zone
Core
Structure of the Sun

The structure of the Sun consists of the
parts shown in Figure 9.1. Carry out
Activity 9.1 to learn more about the
structure of the Sun.

Corona

Three layers that form
the Sun’s atmosphere Chromosphere

Photosphere

Figure 9.1 Structure of the Sun

Activity 9.1

To gather and share information on the structure of the Sun
consisting of the core, radiation zone, convection zone, photosphere, • ICS, ISS

chromosphere and corona • Discussion

Instructions activity

1. Work in groups.
2. Gather information from the Internet, printed media and other electronic media
on the structure of the Sun consisting of the core, radiation zone, convection zone,
photosphere, chromosphere and corona.
3. Discuss and share the information gathered.
4. Present the outcome of your group discussion using multimedia presentation.

258 9.1.1

Phenomena that Occur on the Chapter 9: Space Weather
Surface of the Sun
Science Careers
Phenomena that occur on the surface of the Sun include:
• Granules A career as a solar scientist is
• Sunspots relatively new in the field of solar
• Solar cycles energy. Besides inventing solar
• Prominences energy equipment, a solar scientist
• Solar flares also studies and forecasts space
• Coronal mass ejections weather which greatly affects daily
• Solar winds life on Earth.

Granules, Sunspots and Solar Cycle Sunspot Granule
Figure 9.2 Granules and sunspots
The photosphere in the Sun’s atmosphere is made
up of granules which appear as grainy structures.
The granules are the upper part of the convection
zone of the plasma which is extremely hot with
a temperature as high as 5 800°C. The
average diameter of a granule is
about 1 000 kilometres!

Sunspots are the dark regions
seen on the surface of the Sun as
shown in Figure 9.2. Sunspots appear
dark because their temperatures are
lower than their surrounding areas
which are made up of granules.
Sunspots are the locations of very
large eruptions in the photosphere.
This phenomenon may last more than
a week. Sunspots are phenomena that
always exist in pairs or groups.

The activity of the sunspots seems to
appear and disappear according to a cycle
that lasts 11 years known as the solar cycle.
Figure 9.3 shows the position of sunspots in
the photosphere since 1875.

60°N
30°N

Equator
30°S
60°S
1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020
(Source: NASA)

Figure 9.3 Position of sunspots on the surface of the Sun
9.1.1 259

Prominence Photograph 9.2 Prominence
Photograph 9.3 Solar flare
A prominence shown in Photograph 9.2 is a huge loop
or arched column of glowing gases over the sunspot.
Prominences can reach heights of hundreds of thousands
of kilometres and may last for several days or months.
Prominences that are very strong can throw out matter from
the Sun into space at speeds ranging from 600 km s-1 to
more than 1 000 km s-1.

Solar Flares

A solar flare shown in Photograph 9.3 is a column of large
amounts of charged gases erupting from the Sun and often
occurs near sunspots. Solar flares are strong and spectacular
explosions of gases. Solar flares attain their maximum
brightness level within a few seconds or minutes and then
become dim after a few minutes or hours. Solar flares spout
charged gas particles at high speeds into outer space. The
light from solar flares which is at the speed of light takes
eight minutes to reach Earth while the charged gas particles
take tens of minutes.

These charged gas particles often collide with atoms and
molecules in Earth’s atmosphere to produce a stunning light
display in the sky known as aurora which uniquely occurs
only in the air space around Earth’s poles.

Coronal Mass Ejections Photograph 9.4 Coronal mass ejection

A coronal mass ejection shown in Photograph 9.4 is a huge Watch a video on prominences,
cloud of plasma that erupts from the Sun and often occurs solar flares and coronal mass
together with solar flares which are huge and strong. A ejections.
coronal mass ejection is an ejection of magnetic gas particles.
The coronal mass ejection spouts magnetic particles at high *(5
speeds into outer space and appears like an expanding cloud.
These magnetic particles from the coronal mass ejection take
three days to reach Earth.

Like the charged gas particles in solar flares, the magnetic
gas particles also react with atoms and molecules in Earth’s
atmosphere to produce aurora.

:
.,
7(

260 9.1.1

Chapter 9: Space Weather

Solar Wind Solar wind Earth

Particles in plasma such as electrons, protons and
alpha particles that erupt from the Sun to outer
space travel together at high speeds known as
solar wind as shown in Photograph 9.5.

Solar wind also carries the interplanetary
magnetic field along with it. The speed of solar
wind is supersonic with values ranging from
250 km s-1 to 750 km s-1. However, the speed,
temperature and density of the solar wind
changes along the course of its movement.

Photograph 9.5 Solar wind (in yellow)

Earth’s Magnetosphere and its Importance

Shape of Earth’s Magnetosphere

Magnetosphere

Solar wind Earth

Magnetosphere

(a) Earth’s magnetic field (b) Earth’s magnetosphere

Figure 9.4 Shape of Earth’s magnetosphere

Compare and contrast the pattern of magnetic field lines between Earth’s magnetic field and

Earth’s magnetosphere. Even though both of these patterns

of magnetic field lines are not fixed, the pattern of Earth’s MARVELS OF
magnetic field lines changes slightly while the pattern of SCIENCE
the magnetic field lines in the magnetosphere changes a lot
based on the interaction between solar wind and Earth’s Animation that shows
magnetic field. the relationship between
magnetosphere and solar wind.

Definition of Earth’s Magnetosphere http://links.andl17.com/BT_
Science_261
Earth’s magnetosphere is defined as a region in outer
space surrounding Earth where the magnetic field in Earth’s 261
magnetosphere is a combination of Earth’s magnetic field
(as the prime magnetic field) and the magnetic field in the
region in outer space as shown in Figure 9.4(b).

9.1.2

Formation of Earth’s Magnetosphere

Magnetosphere is formed by the interaction between the magnetic field brought by the solar
wind and Earth’s magnetic field. As the number and energy of particles brought by the solar
wind change, the shape of the magnetosphere also changes.

Importance of Earth’s Magnetosphere

The importance of magnetosphere is to protect Earth from the adverse effects caused by
dangerous particles from the Sun or other bodies in the Universe.

Solar wind Magnetosphere
(in yellow) (magnetic field lines
in blue)

Earth protected
by magnetosphere

Magnetosphere
(magnetic field lines
in blue)

Figure 9.5 Protection from Earth’s magnetosphere

The magnetosphere:
• functions as a biological shield to protect life on Earth from the adverse effects of solar wind
• blocks charged particles such as electrons, protons and alpha particles in the solar wind from

reaching Earth. Excessive numbers of charged particles in Earth’s atmosphere will disrupt
telecommunication, navigation system and electric power lines
• reduces the pressure exerted by solar wind on Earth’s atmosphere

Activity 9.2

To gather and share information on the definition, formation, shape
and importance of the magnetosphere • ICS, CPS, ISS

Instructions • Discussion

1. Work in groups. activity

2. Gather information from the Internet, printed media and other electronic media on
the definition, formation, shape and importance of the magnetosphere.
3. Discuss and share the information gathered.
4. Brainstorm on the condition of Earth without the magnetosphere.
5. Present the outcome of your group discussion using multimedia presentation.

262 9.1.2

Chapter 9: Space Weather

Formative Practice 9.1

1. State three structures of the Sun that form the Sun’s atmosphere.
2. State three phenomena that occur on the surface of the Sun where charged gases erupt.
3. Define Earth’s magnetosphere.
4. What influences the shape of the magnetosphere?
5. Name one object in the Solar System that has the same shape as solar wind.

9.2 Space Weather

Space Weather and its Effect on Earth Websites

Space weather is defined as the phenomena that occur: Space weather
• on the surface of the Sun such as solar flares,

prominences, sunspots and coronal mass ejections
• in space such as solar wind, solar radiation storm and

geomagnetic storm

http://links.andl17.com/BT_
Science_263

Study Figure 9.6. Then, carry out Activity 9.3.

Sunspot Coronal mass ejection Magnetic field
Solar wind line

Earth Solar radiation storm Earth

Magnetic field
line

Solar flare

Geomagnetic storm
Figure 9.6 Space weather

9.2.1 263

Activity 9.3

To gather and share information on the definition of space weather
and its effects on Earth
• ICS, CPS, ISS

Instructions • Discussion
1. Work in groups. activity

2. Gather information from the Internet, printed media and other electronic media on
the definition of space weather and effects on Earth such as the formation of the
aurora, disturbances to telecommunication, navigation system as well as electrical
power lines.

Space storms Effects of geomagnetic
http://links.andl17.com/ storm, solar radiation
BT_Science_264_1 storm and disturbances
of radio transmission
http://links.andl17.com/
BT_Science_264_2

3. Discuss and share the information gathered.
4. Present the outcome of your group discussion using multimedia presentation.

Interpretation of Data on Space Weather

Data on space weather is used or analysed to:
• forecast when coronal mass ejections occur in the Sun
• determine the reasons for the occurrence of solar flares and coronal mass ejections on the

surface of the Sun

Activity 9.4 • ICS, CPS, ISS
• Discussion
To interpret data on space weather
Instructions activity
1. Work in groups.
2. Gather information or data on space weather from the Internet,

printed media and other electronic media.

Sources of solar wind in relation to solar cycle
http://links.andl17.com/BT_Science_264_3

3. Interpret data on space weather by relating the number of sunspots or solar cycles
with the increase in coronal mass ejections and solar winds.

4. Present your group’s interpretation of space weather data using multimedia presentation.
264 9.2.1

Chapter 9: Space Weather

Formative Practice 9.2

1. What is the definition of space weather?
2. State four examples of the effects of space weather on Earth.
3. What is the relationship between the number of sunspots and the increase in coronal

mass ejections?

Summary

Space weather

is influenced by

Sun Solar wind Phenomena on the
surface of the Sun

which determines the shape of the produce effects
such as

Structure Phenomena on Magnetosphere Formation of aurora,
its surface which disturbances to
Core, radiation telecommunication,
zone, such as navigation system as well
convection as electric power lines
zone, Granules, Protects
photosphere, prominences, Earth which shows
chromosphere, solar flares,
corona solar cycles, from The relationship
sunspots, between the number of
coronal mass Adverse effects sunspots (solar cycle),
ejections, from harmful and the increase in
solar winds particles in coronal mass ejections
solar winds and solar winds

265

Self-reflection

After studying this chapter, you are able to:

9.1 Activities of the Sun that Affect Earth
Explain the structure of the Sun and phenomena that occur on the Sun's surface
by drawing.
Justify the importance of Earth’s magnetosphere.

9.2 Space Weather
Communicate space weather and its effects on Earth.

Summative Practice 9 D:

Answer the following questions:
1. Figure 1 shows the structure of the Sun.

A:

B: E:

C:
F:

Figure 1

Name the structures labelled A to F using the following words:

Photosphere Corona Chromosphere

Core Convection zone Radiation zone

2. What is the duration of one solar cycle?
3. State the phenomenon related to solar cycle.

266

Chapter 9: Space Weather

4. State three examples of equipment or service used daily which is disrupted by solar
winds.

5. What would happen to the condition of Earth if there is no magnetosphere?
Explain your answer.

Focus on HOTS

6. Earth’s magnetosphere shown in Figure 2, is a region in space which protects Earth.

Figure 2
The shape of Earth's magnetosphere is produced by the interaction between Earth’s
magnetic field and solar wind. Magnetic field lines from other planets in the Solar System
are represented by white lines while Earth’s magnetic field lines are represented by red lines
as shown in Figure 2.
You are required to create a model of the magnetosphere using the following materials:

• Green-coloured plastic bag
• White thread
• Red thread
• Polystyrene cup with a convex cover
• Plasticine

Sketch the model of the magnetosphere. Explain how the model functions.

267

CChhaapptteerr

1001 Space Exploration

How can the model of the Solar
System be improved from time
to time?
Give three examples of
technological invention devices
applied in space exploration.
Give an example of the use of
remote sensing technology in
field of geology.

Let’s study

Development in astronomy
Development of technology and its application in space exploration
268

Science Gallery

International Space Station, ISS

The International Space Station (ISS) is a
station that facilitates international research
in space. The function of this station
is to carry out research in space and
monitor space.

Dato’ Dr Sheikh
Muszaphar Shukor Al Masrie
bin Sheikh Mustapha is the
first astronaut from Malaysia
to carry out experiments in
space from 10 October to
21 October 2007.

Keywords Satellite
Space probe
Geocentric Remote sensing
Heliocentric Geology
Kepler’s Law Disaster management
Ellipse Space Telescope
Focal point
Rocket 269

10.1 Development in Astronomy

Historical Development of the Solar System Model

Study Figure 10.1. Then, carry out Activity 10.1.

History of the Solar System Model

Ptolemy Copernicus
o " %
o


t (SFFL BTUSPOPNFS
t 1PMJTI BTUSPOPNFS

BTUSPMPHFS BOE NBUIFNBUJDJBO

HFPHSBQIFS FDPOPNJTU BOE EPDUPS

t #VJMU UIF geocentric t #VJMU UIF heliocentric
NPEFM XJUI &BSUI BU NPEFM XJUI UIF 4VO BU
UIF DFOUSF BOE UIF DFOUSF BOE DJSDVMBS
DJSDVMBS PSCJUT PSCJUT

Geocentric model Heliocentric model

Jupiter

Jupiter Mercury Mars

Mars Venus Saturn
Sun
Earth Mercury
Venus Moon
Saturn Earth
Sun Moon

t A(FP NFBOT &BSUI t A)FMJP NFBOT UIF 4VO
t A$FOUSJD NFBOT DFOUSF t A$FOUSJD NFBOT DFOUSF
t &BSUI JT BU UIF DFOUSF PG UIF 4PMBS 4ZTUFN t 5IF 4VO JT BU UIF DFOUSF PG UIF 4PMBS 4ZTUFN
t &BSUI JT TUBUJPOBSZ BOE BMM UIF PCKFDUT TVDI BT t &BSUI SPUBUFT PO JUT BYJT BOE SFWPMWFT BSPVOE

UIF 4VO BOE PUIFS QMBOFUT SFWPMWF BSPVOE UIF 4VO JO B DJSDVMBS PSCJU
&BSUI JO DJSDVMBS PSCJUT
Figure 10.1 History of the Solar System model
270 10.1.1

Chapter 10: Space Exploration

Kepler
o


tø (FSNBO BTUSPOPNFS
NBUIFNBUJDJBO
BOE BTUSPMPHFS

t .PEJmFE UIF heliocentric NPEFM XJUI
UIF 4VO BU POF DPNNPO GPDBM QPJOU PO
UIF FMMJQUJDBM PSCJUT PG UIF QMBOFUT
BDDPSEJOH UP Kepler’s Law

Modified Heliocentric model according to Kepler’s Law

8 5
7 6

4 2
3
1 Sun

1 .FSDVSZ 4 .BST 7 6SBOVT
2 7FOVT 5 +VQJUFS 8 /FQUVOF
3 &BSUI 6 4BUVSO
271
10.1.1

Activity 10.1

To understand the development of the Solar System models built by • ICS
Ptolemy, Copernicus and Kepler
• Discussion

Instructions Activity

1. Work in groups.
2. Carry out active reading by visiting websites or going on a study tour to the National
Planetarium to gather information on the development of the Solar System models
built by:
(a) Ptolemy
(b) Copernicus
(c) Kepler
Examples of websites are as follows:

Watch these sections Historical attempts to
of the video model the Solar System
3.01 Historical Solar (Take a challenge)
http://links.and l17.com/
System Models BT_Science_272_2
3.02 Current Solar

System Model
http://links.and l17.com/
BT_Science_272_1

History of the Solar System model
http://links.and l17.com/BT_Science_272_3

3. Discuss and present to the class how knowledge gained through scientific research is
the product of human effort to obtain rational explanations about natural phenomena.

4. Present the outcome of your group discussion using multimedia presentation.

Formative Practice 10.1

1. Name the Solar System model built by the following astronomers:
(a) Ptolemy
(b) Copernicus
(c) Kepler

2. Compare and contrast the Solar System models built by Ptolemy and Copernicus.
(a) Similarities
(b) Differences

3. Compare and contrast the Solar System models built by Copernicus and Kepler.
(a) Similarities
(b) Differences

272 10.1.1

Chapter 10: Space Exploration

10.2 Development of Technology and its
Application in Space Exploration

Development in Space Exploration

Figure 10.2 shows part of the early history of space exploration in terms of technology
development and missions in space exploration.

2011: Construction of International 2002: National Space 2000:
Space Station (ISS) completed Agency (Agensi Angkasa Malaysia’s
Negara) established first
microsatellite
TiungSAT-1
launched

1981: First 1989: First Neptune 1990: US launched 1996: Malaysian
flight of US flyby – US Voyager 2 Hubble Space Telescope satellites MEASAT 1
space shuttle from space shuttle and 2 launched
– Columbia Discovery

1973: First Jupiter flyby – US 1969: First human to 1961: First human to orbit Earth –
Pioneer 10 set foot on the Moon – Yuri Gagarin, aboard USSR Vostok 1
Neil Armstrong,
US Apollo 11

1609: First telescope used in the 1957: First satellite – USSR Sputnik 1
field of astronomy by Galileo Galilei
11th century:
Chinese invented
gunpowder and
used primitive
rockets in battles

Figure 10.2 Some of the events related to the development of technology
in space exploration

10.2.1 273

Applications of Technology in Space Exploration and their
Importance

Space Telescope
Figure 10.3 shows the development of the telescope.

The astronomical sextant is Galileo’s Telescope became Hubble space telescope
used to measure the altitude the most widely used was placed in an orbit 500 km
of stars astronomical instrument from the surface of Earth

The Spitzer space telescope
detects very distant activities
in space.

Apart from optical telescopes, radio
telescopes are also used to detect radio
waves from space.

Figure 10.3 Space telescopes

Rocket

Rockets are used widely in space
explorations. When the fuel in a rocket
burns, hot gases are released at high speed
through the bottom of the rocket. The
release of these gases produces a force
which pushes the rocket upwards.

Vostok K Redstone Atlas Voskhod Titan II Soyuz Saturn 1B Saturn V STS Long Falcon SLS Angara Atlas V

March 2F 9 5P

Photograph 10.1 Rockets used to send humans to space

Based on Photograph 10.1, which rocket was used to send astronauts to the Moon?

274 10.2.1

Chapter 10: Space Exploration

Satellite Photograph 10.2 Weather Websites
satellite GOES-16 gathers
The first satellite, data on solar flares Satellite launch
Sputnik 1 was sent to
outer space in 1957. http://links.and l17.com/BT_
How many satellites are Science_275
orbiting around Earth
today? Which country
has the largest number
of satellites?

Space Probe MARVELS OF
SCIENCE
A space probe is a spacecraft
In 2017, space probe Cassini was
that gathers information and still active orbiting Saturn even
after 20 years in space.
sends it back to Earth. Space

probes do not orbit Earth like

satellites but travel further

into and out of the Solar Photograph 10.3 Space
System. Space probes carry probe Cassini
cameras and remote sensing

instruments as well as radio

transmitters and receivers for the purpose of

communicating with scientists on Earth.

Remote Sensing

Remote sensing is a method of gathering and recording information from a distance. In

Malaysia, remote sensing instruments are fitted to TiungSAT-1 to receive or detect visible,

ultraviolet and infrared lights produced by objects on the surface or below the surface of

Earth. The information gathered by TiungSAT-1 is then sent to two data receiving stations at

the National Planetarium Station, Federal Territory of Kuala Lumpur and the Mission Control

Station (MCGS), Bangi, Selangor.

Photograph 10.4 shows the pattern and movement of

clouds taken from TiungSAT-1’s remote sensing camera.

What is the use of the information obtained from this

photograph?

Remote sensing technology is used in various fields in

daily life as follows:

• Agriculture – To detect suitable regions for agricultural

development

• Geology – To detect locations such as mineral sources,

mass depletion and land depletion Photograph 10.4 A picture of

• Disaster management – To identify pollution and forest fires the pattern and movement of

• Defence – To detect intrusions of enemy ships, aircraft and clouds

vehicles

10.2.1 275

Activity 10.2

To understand the development of technology in space exploration

• ICS

Instructions • Discussion

1. Work in groups. activity

2. Carry out active reading by visiting websites or going on a study
tour to the National Planetarium, MACRES and National Space Agency to gather
information on the development of technology in space exploration in:
(a) early history of space exploration
(b) the construction of rocket, satellite and space probe
(c) remote sensing used in agriculture, geology, disaster management and defence
3. Discuss and present the development and technological applications in space
exploration and their importance.
4. Present the findings of your group discussion using multimedia presentation.

Activity 10.3

To debate the issue of continual space exploration

• ISS, CPS

Instructions • Project-based

1. Work in groups. activity

2. Gather information from the Internet, printed media and other
electronic media on the importance of space exploration in the local and global
context.
3. Share and discuss the gathered information.
4. Debate the issue of continual space exploration in the local and global context.

Formative Practice 10.2 Hape
Discovery
1. Name the first technological device used in space exploration.
Figure 1
2. Study Figure 1.
(a) What is Discovery?
(b) What is Hape?

3. (a) Name the technology used to take aerial photographs.
(b) What is the importance of taking aerial photographs
during floods?

4. What is the role played by the Malaysian Remote Sensing Agency
(MACRES)?

276 10.2.1 10.2.2

Summary

Space exploration

is infuenced by

Development in astronomy Development of technology and its
application in space exploration
such as
such as
Building of solar
system models Rocket Satellite Space probe

by

used to used to used to

Ptolemy Copernicus Kepler

Earth as the Sun as the Sun as the Send spaceships, Gather information Gather and send
centre of the centre of the centre of the satellites, space on space weather, information on
Solar System Solar System Solar System probes to space remote sensing, distant bodies in
telecommunication, space
with defence
Chapter 10: Space Exploration
Earth and
277 other planets
with revolving in
with elliptical orbits

Sun and other Earth and Remote sensing used in
planets other planets
revolving in revolving in Agriculture, geology,
circular orbits circular orbits disaster management,
defense

Self-reflection

After studying this chapter, you are able to:
10.1 Development in Astronomy

Explain the historical development of the Solar System model by drawing.
10.2 Development of Technology and its Application in Space Exploration

Communicate the importance of the development of technology and its application in
space exploration.
Justify the need to continue space exploration.

Summative Practice 10

Answer the following questions:
1. Figure 1 shows the Spitzer space telescope.

Figure 1

Mark ‘✓’ for the correct statements and ‘×’ for the incorrect statements.

(a) The Spitzer space telescope is located on the surface of Earth.
(b) The Spitzer space telescope ‘observes’ better than ordinary telescopes.
(c) The Spitzer space telescope is used to take photographs of Earth’s

surface.
(d) The Spitzer space telescope is used as a remote sensing equipment.

278

Chapter 10: Space Exploration

2. Match the Solar System model to the astronomer who built it. Astronomer
Solar System model

(a) Earth is at the centre of the Copernicus
Solar System and the Sun Kepler
revolves around Earth in a Ptolemy
circular orbit.

(b) The Sun is at the centre of
the Solar System and Earth
revolves around the Sun in
an elliptical orbit.

3. How can knowledge about astronomy be acquired through scientific investigation?
4. Why are space probes not used to send astronauts into space?
5. Figure 2 shows a space probe sent to Saturn.

Figure 2

(a) What is the function of this space probe?
(b) State one example of a phenomenon that occurs on the surface of the Sun that might

destroy the space probe.
(c) State the source of energy used by the space probe.

6. State two examples of the use of remote sensing technology in the following fields:
(a) Agriculture
(b) Geology
(c) Disaster management
(d) Defence

279

Focus on HOTS

7. Figure 3 shows a rocket.

Figure 3
(a) What is a rocket?
(b) What is the function of rocket in space exploration?
(c) Explain one misuse of rocket in our daily life.
8. Astronomers have successfully discovered three planets revolving around the TRAPPIST-1
star which are suitable for all life on Earth.
As these three planets are extremely far, a special spacecraft needs to be invented to
transfer life on Earth to these planets.
You are required to invent a model of the spacecraft using the following materials:

• Cardboard
• Cellophane tape
• Black plastic sheet
• Aluminium foil

280

ANSWERS

CHAPTER 1 Stimuli and Formative Practice 1.1 (p. 10)
Responses 1. Central nervous system and peripheral

Activity 1.1 (p. 7) nervous system
Questions 2. (a) Voluntary actions are conscious
1. Stimulus: Seeing your partner let go of
actions, carried out according to the
the ruler. wishes of a person and are controlled
Response: Catching the ruler using your by the brain.
Examples of controlled actions are
thumb and index finger. reading, writing, speaking, eating,
This is a voluntary action drinking, walking, running, exercising
because it is a conscious and singing.
action and is made according (b) Involuntary actions are spontaneous
to the will of the individual actions that happen without being
who received the stimulus realised or thought of beforehand.
and is controlled by the brain. Examples of uncontrolled actions
2. The distance moved by the ruler shows are heartbeat, breathing, peristalsis,
the time taken by the student to catch secretion of saliva and sneezing.
the ruler. The shorter the distance, the 3. Injured nerve cells in the human brain
faster the reaction time. are unable to interpret impulses from
3. Different students usually have different affectors and cannot send impulses to
reaction time. Besides this, the reaction effectors. Due to this, a person who
time of an individual is not constant. sustained brain injury is unable to carry
4. In the daily life of humans, reaction time out voluntary or involuntary actions
plays an important role to coordinate and involving the brain.
control organs and body parts so that 4. The network of nervous system of
they function harmoniously and efficiently. humans functions to control and
coordinate organs and body parts so as
Activity 1.3 (p. 9) to carry out processes in the body and
Questions daily activities.
1. Stimulus: Intensity of light that enters
Brain Teaser (p. 15)
the eye. Excess mucus is produced when a person
Response: Change in size of the pupil. suffers from a cold. This excess mucus will
obstruct receptors from being stimulated by
This is an involuntary action chemical substances in the air entering the
because this action occurs nasal cavity.
spontaneously without any
conscious control or prior Brain Teaser (p. 16)
thoughts. A blind person uses the sensitivity of the
2. The higher the intensity of light, the fingertip to read Braille and sensitivity of the
smaller the size of the pupil. hand to detect vibrations of the walking stick
3. This response can help protect the eye when it hits objects to detect any nearby
from injury. obstructions.

Brain Teaser (p. 10)

Muscular system

1

Activity 1.6 (pp. 19, 20) substances in hot food also evaporate to
Questions form vapour which enters the nasal cavity
1. Tip of index finger. It has the largest and stimulates the smell sensory cells.
The combination of sense of taste and
number of receptors. sense of smell causes hot food to taste
2. Elbow. It has the least number of better.

receptors. Formative Practice 1.2 (p. 29)
3. Touch receptor. 1. (a) Cornea
4. Number of touch receptors and thickness
(b) Pupil
of epidermis. (c) Retina
(d) Brain
Activity 1.7 (p. 21) 2. Semicircular canals
Questions 3. At the upper part of the nasal cavity
1. To ensure no other solutions remain and 4. Sweet, sour, salty, bitter, umami
5. Number of receptors and thickness of
only the taste of one solution is detected skin epidermis
during each attempt. 6. (a) Five types of taste, touch, pain, hot
2. All areas of the tongue can detect all
tastes of the solutions. objects, cold objects, and pressure.
3. Both sides of the tongue are most (b) Five types of taste can be detected
sensitive towards taste because they
have a large number of taste receptors. by taste receptors in the taste
4. The middle part of the tongue is least buds of the tongue. The tongue is
sensitive to taste because it has a small protected by skin that has touch,
number of taste receptors. pain, heat, cold and pressure
5. The front part of the tongue is more receptors. Therefore, it can detect
sensitive to sweet taste, the sides of touch, pain, hot objects, cold objects
the tongue are more sensitive to sour and pressure.
and sweet tastes, the back part of the
tongue is more sensitive to bitter taste Experiment 1.1 (pp. 30 – 33)
and the middle part of the tongue is more A. Questions (p. 31)
sensitive to umami.
1. Light
Brain Teaser (p. 22) 2. Shoot of the plant
No. After the tongue is cleaned, the tongue 3. The shoot of the plant shows positive
will become more sensitive.
phototropism because shoots of
Activity 1.8 (pp. 22, 23) plants grow towards the direction of
Questions light.
1. Without the nose being pinched.
2. Taste of the cordial drink is more easily B. Questions (p. 32)
1. So that light cannot influence the
detected using a combination of sense of growth of the seedlings.
taste and sense of smell. 2. (a) Grow upwards against the
3. So that your partner does not use sense direction of gravity.
of sight to determine the taste of the (b) Grow downwards in the direction
cordial drink based on the colour such as of gravity.
purple for taste of grape, orange for taste 3. Roots of plants show positive
of orange, yellow for taste of mango and geotropism because the roots of
red for taste of strawberry. plants grow towards the direction of
4. In addition to chemical substances gravity. Shoots of plants show negative
in food which dissolve in saliva and geotropism because shoots of plants
stimulate the taste buds, chemical grow against the direction of gravity.

2

C. Questions (p. 33) cat received by both of Azman’s ears are
1. Water the same. The brain then informs Azman
2. Roots of the plant the direction of the cat making the sound.
3. Absorbs water and moisture in the air
in beaker Y Summative Practice 1 (pp. 41 – 43)
4. The roots of the plants show positive
hydrotropism because they grow 1. (a) ×
towards water.
(b)
Formative Practice 1.3 (p. 35)
1. (a) Tropism is a directed response of (c) ×

plants towards stimuli coming from a (d)
certain direction. 2. P: Brain
(b) (i) Thigmotropism
(ii) Geotropism Q: Spinal cord
(iii) Phototropism R: Peripheral nerve
2. (a) (i) Shoots 3. (a) Changes in the size of the pupil of
(ii) Roots
(iii) Tendrils or winding shoots the eye.
(b) Positive hydrotropism allows roots to (b) Intensity of light which enters the eye.
obtain water and dissolved mineral (c) The lower the intensity of light
salts to survive.
3. Similarity: Tropism and nastic response directed towards the eye, the larger
the size of the pupil of the eye.
are responses of plants (d) During a solar eclipse, the bright
towards stimuli. rays of the sun will enter the eye and
Difference: Tropism is the directed damage the cells of the retina.
response of plants towards 4. (a) Sound → Earlobe → Ear canal →
stimuli while nastic response Eardrum → Ossicles → Oval window
is the response towards → Cochlea → Auditory nerve → Brain
stimuli without considering (b) Light → Cornea → Aqueous humour
their direction. → Pupil → Eye lens → Vitreous
humour → Retina → Optic nerve →
Brain Teaser (p. 37) Brain
The blind have a more sensitive sense of 5. (a) X: Touch receptor
hearing. They make use of sound to detect Y: Pain receptor
location and estimate distance of nearby (b) Fingertip is more sensitive towards
objects. touch stimuli compared to the palm
of the hand.
Formative Practice 1.4 (p. 39) Fingertip has a thinner layer of
1. Stereoscopic and monocular vision. epidermis and more touch receptors
2. Location of eyes on the head. compared to the palm of the hand.
3. Primary consumer has monocular vision. (c) Agree. The tongue is a sensory
organ that has receptors known as
Monocular vision has a wide field of taste buds on the surface of the
vision and allows it to detect predators tongue which is protected by skin
coming from various directions. epidermis.
4. Stereophonic hearing allows us to 6. (a) The sense of smell helps us to detect
determine the direction of sound danger such as leakage of gas that
accurately. might occur in the science laboratory.
5. Azman uses his stereophonic hearing For example, we can detect the
to determine the cat’s location. The time presence of dangerous gases such
and loudness of the sound made by the as chlorine and ammonia from their
smell.
(b) Dogs have a very sensitive sense
of smell because they have more
sensory cells for smell than human

3

and are more efficient to analyse 3. To provide sufficient oxygen and
smell than human. eliminate carbon dioxide from the air.
7. (a) – Positive phototropism
– Positive hydrotropism 4. (a) (i) Rib cage
(b) Positive phototropism ensures shoots (ii) Diaphragm
and leaves of plants obtain sufficient (iii) Trachea and bronchus
sunlight to make food through (iv) Lungs
photosynthesis.
Positive hydrotropism allows roots (b) – A thin rubber sheet stretches more
of plants to grow towards water so easily compared to a thick rubber
that they can absorb water to enable sheet.
plants to carry out photosynthesis.
8. (a) Stereoscopic vision – Therefore, a thin rubber sheet is
(b) The eagle is a predatory animal. more easily pulled downwards or
Stereoscopic vision helps the pushed upwards.
eagle to hunt its prey by accurately
determining the location of its prey. (c) (i) Breathing in or inhaling
9. Explanation: (ii) Exhaling
– Fill the transparent plastic bottle with
water. (d) – The structure or volume of the
– It functions as a convex lens. glass jar which represents the rib
– Place it on top of the newspaper. cage is fixed when the thin rubber
– Read the newspaper through it. sheet is pulled downwards or
pushed upwards.
CHAPTER 2 Respiration
– While the structure and volume of
Experiment 2.1 (pp. 50 – 52) the rib cage changes during the
Question (p. 51) processes of inhaling or exhaling.
– The water level in the gas jar containing
Formative Practice 2.2 (p. 56)
inhaled air is higher. 1. Difference in concentrations of oxygen
– Composition of oxygen in inhaled air is
gas in the alveolus and blood capillaries.
higher than that in exhaled air. 2. (a) When concentration of oxygen is
– Burning of candle using the oxygen in the
high, haemoglobin will combine
gas jar causes water to enter to fill the with oxygen chemically to form
space originally filled with oxygen. oxyhaemoglobin which is unstable.
(b) When concentration of oxygen is low,
Question (p. 52) oxyhaemoglobin will decompose to
– Limewater in the conical flask where form haemoglobin and oxygen.
3. Glucose + oxygen → carbon dioxide +
exhaled air was passed through turns water + energy
cloudy. 4. Efficiency of exchanging oxygen in the
– Carbon dioxide in the exhaled air reacts human body decreases at high altitudes.
with the limewater. Concentration of oxygen in the air at high
altitudes is low. Due to this, the rate of
Formative Practice 2.1 (p. 53) diffusion of oxygen from the alveolus into
1. (a) Trachea the blood capillaries is also low.
5. – Thickness of wall of alveolus and
(b) Bronchus blood capillary is one cell thick
(c) Bronchiole – The wall of alveolus is moist
2. (a) – Alveolus with large surface area
– Dense network of capillaries covering
(b) × alveolus
(c) ×
(d) × Brain Teaser (p. 57)
Forests help to maintain the balance of oxygen
4 and carbon dioxide in the atmosphere.

Brain Teaser (p. 58) to this, the health of all systems in the
Smoking endangers the health of the smoker body especially the respiratory system is
and everyone in the vicinity of the smoker. maintained.
5. Not smoking, frequent exercise
Brain Teaser (p. 59)
Electric buses do not emit exhaust gases. Brain Teaser (p. 67)
Therefore, air pollution can be reduced. Organ of gaseous exchange.

Experiment 2.2 (pp. 62, 63) Brain Teaser (p. 71)
Questions Air is always moving from one region to
1. Cigarette tar another region. Therefore cooperation from
2. Cigarette smoke is an acidic substance the global society is required. Prevention in
only one region would not be effective.
because it changes the purple colour of
litmus solution to red. Formative Practice 2.5 (p. 72)
3. Ammonia, stearic acid, methane, butane,
methanol, toluene, cadmium, arsenic, 1. Leaves, stem, aerial roots
acetone
2. P: Guard cell Q: Stomatal pore
Formative Practice 2.3 (p. 63)
1. (a) Tar, pollen, haze and dust 3. (a) Stomata open during the day. Water

(b) Sulphur dioxide, carbon monoxide, diffuses into guard cells through
nitrogen dioxide
osmosis causing the guard cells to
2. Pollen
3. (a) Pain during breathing bend and open the stoma.

(b) Blood in phlegm (b) Stomata close at night. Water
(c) Frequent shortness of breath
(d) Wheezing sound when breathing diffuses out of guard cells through
4. Lung cancer, emphysema, bronchitis,
(any two) osmosis causing the guard cells
5. A person who does not smoke but
who breathes in cigarette smoke from to straighten up and close the
smokers nearby.
stoma.
Formative Practice 2.4 (p. 66)
1. (a) Gills (c) Stomata are closed on hot days

(b) Trachea to prevent excessive loss of water
(c) Moist outer skin
2. Thin outer skin of frogs, dense network through transpiration.
of blood capillaries under the layer of
skin, very permeable to respiratory gases 4. Polluted air will reduce the amount of
and moist.
3. Body cells of insects have a direct sunlight reaching the plants and reduce
connection with the respiratory surface.
Oxygen that enters the tracheole diffuses the rate of photosynthesis. Hence, the
directly into the cells while carbon dioxide
diffuses out. growth and survival of plants will be
4. When we exercise, our rate of respiration
increases. Higher rate of transport of jeopardised.
oxygen to body cells and higher rate of
elimination of carbon dioxide from body Summative Practice 2 (pp. 74 – 77)
cells result in healthier body cells. Due 1. (a) Alveolus

(b) Bronchus
(c) Nasal cavity
2. P: Trachea
Q: Bronchus
R: Alveolus
3. (a)
(b)
(d)
4. (a) higher
(b) lower
5. (a) Haemoglobin transports oxygen from

the red blood cell to body cells.
(b) Oxyhaemoglobin easily decomposes

into haemoglobin and oxygen when

5

it reaches body cells so that oxygen gaseous exchange
can diffuse into the cells. in the alveolus is
6. (a) Azura may be allergic to pollen. In reduced causing
Spring, more pollen is released from shortness of breath.
anthers. When Azura inhales air 8. – Stop smoking.
containing pollen, there is a higher To avoid harmful substances found
risk of her getting an asthma attack. in cigarette smoke from entering the
(b) Any place that is hazy and dusty. lungs and harming the respiratory
Examples: industrial areas, system.
construction sites and others. – Avoid places with polluted air.
Haze and dust also cause asthma To avoid inhaling air that contains
attacks in asthma patients. harmful substances such as cigarette
7. (a) – Thickness of the wall tar, carbon monoxide, sulphur dioxide,
– Moisture of the wall nitrogen dioxide, haze, dust and pollen
– Surface area which are harmful to the respiratory
– Network of capillaries system.
(b) (i) Asthma – Have proper exercise and lead a
healthy lifestyle.
Symptom: Shortness of breath To maintain a healthy respiratory
Cause: Excessive release system.
9. Users at the waiting areas will become
of mucus on the passive smokers if there are other users
surface of alveolus nearby who smoke. This is harmful to
reduces the surface their health.
area and rate of 10. (a) Gaseous exchange is through
gaseous exchange in diffusion into cells.
the alveolus thereby (b) The respiratory system of insects
causing shortness of is more effective than the human
breath. respiratory system.
(ii) Bronchitis (c) Gaseous exchange through direct
Symptom: Shortness of breath diffusion into the cells of insects is
Cause: Inflammation of the easier, quicker and more efficient
bronchus in bronchitis compared to gaseous exchange
patients caused through transport of gases by blood
by tar and irritants in the human body.
in cigarette smoke 11. (a) Carbon monoxide
reduces the rate of (b) When the air in a car which
movement of air from contains carbon monoxide is
the nose to the lungs inhaled, the carbon monoxide
through the bronchus. combines with haemoglobin to form
This causes bronchitis carboxyhaemoglobin. Therefore,
patients to be a person in the car will not have
frequently breathless. sufficient oxygen supply which can
(iii) Emphysema be fatal.
Symptom: Shortness of breath 12. (a) (i) 3.0 dm3
Cause: The alveolus in (ii) 2.5 dm3
emphysema patients (b) (i) 4.0 dm3
is damaged by (ii) 3.0 dm3
dangerous substances (c) The more active the activity that is
in the air such as performed, the larger the maximum
irritants in cigarette volume of the lungs. From the graphs
smoke. Hence, the
surface area for

6

in Figures 3(a) and 3(b), the volume – toxic waste products that fail to be
of air in the lungs of runners X and Y eliminated from the body to the outside
increases when they are running. surroundings will poison and kill the
(d) Runner Y. organism.
Cigarette smoke which damages the
alveolus will reduce the maximum Activity 3.2 (p. 84)
volume of air in the human lungs. Fish
The maximum volume of air in the – Fish has a single blood circulatory system
lungs of runner Y is less, therefore
runner Y is a smoker. where blood flows through the heart only
(e) Increase in the maximum volume once in one complete cycle to the all the
of the lungs increases the rate of other parts of the body.
respiration because the rate of – Fish’s heart has one atrium and one
gaseous exchange in the lungs is ventricle.
increased. – Deoxygenated blood flows out from
the heart to the gills where gaseous
CHAPTER 3 Transportation exchange occurs in the capillaries of the
gills changing deoxygenated blood to
Formative Practice 3.1 (p. 82) oxygenated blood.
1. The function of the transport system – Oxygenated blood flows from the heart to
the whole body, changes into deoxygenated
is to carry substances needed by cells blood and flows back into the heart.
into organisms and eliminate waste
products from organisms to the outside Amphibians
surroundings. – Amphibians have an incomplete double
2. Examples of substances needed by cells:
Oxygen, nutrients circulatory system where blood flows
Examples of waste products eliminated through the heart twice in one complete
from cells: cycle to the whole body.
Carbon dioxide, water, urea – Amphibian’s heart has two atriums and
3. Importance of the functions of transport one ventricle.
system in organisms are as follows: – Deoxygenated blood flows out from the
– Transport system provides substances amphibian’s heart to the lungs and skin
where gaseous exchange occurs in the
needed by cells such as oxygen and blood capillary walls in the lungs or under
nutrients which are used to produce the skin changing deoxygenated blood to
energy through the process of cellular oxygenated blood.
respiration. – Oxygenated blood flows from the heart to
– Transport system provides substances the brain and a mixture of oxygenated and
needed by plant cells such as carbon deoxygenated blood flows to all other parts
dioxide and water which are used to of the body except the lungs. Oxygenated
carry out photosynthesis. blood changes into deoxygenated blood
– Transport system also eliminates and flows back into the heart.
toxic waste products from the cells of
organisms to the surroundings. Reptiles
4. If the transport system of an organism – Reptiles have an incomplete double
cannot function well,
– cellular respiration cannot be carried circulatory system where blood flows
out. Without energy, living process through the heart twice in one complete
cannot occur in the organism. cycle to the whole body.
– food cannot be made by green plants – Reptile’s heart has two atriums and one
through photosynthesis. Without food, ventricle with a structure which divides the
plants and animals will die. space in the ventricle into two separate
parts.

7

– Deoxygenated blood flows out from 2. Artery
the heart to the lungs where gaseous
exchange occurs in the walls of the Transports oxygenated blood (except
blood capillaries in the lungs changing the pulmonary artery)
deoxygenated blood to oxygenated blood.
Capillary
– Oxygenated blood flows from the heart to
the whole body except the lungs, changes Connects arteries to veins and is a place
to deoxygenated blood and flows back into of exchange of substances between cells
the heart.
Vein
Mammals and birds
– Mammals and birds have a double Transports deoxygenated blood (except
pulmonary vein)
circulatory system where blood flows
through the heart twice in one complete 3. Type of activity, gender, age, health
cycle to the whole body. 4. Caring for our heart is important to
– The heart of mammals and birds have two
atriums and two ventricles. ensure continuity of our life.
– Deoxygenated blood flows out from
the heart to the lungs where gaseous Brain Teaser (p. 99)
exchange occurs in the walls of the An individual who has blood type O can
blood capillaries in the lungs changing donate blood to all individuals irrespective of
deoxygenated blood to oxygenated blood. their blood type because blood type O does
– Oxygenated blood flows from the heart to not have any antigens on its red blood cells.
the whole body except the lungs, changes
to deoxygenated blood and flows back into Formative Practice 3.3 (p. 101)
the heart. 1. Red blood cells, white blood cells,

Brain Teaser (p. 91) platelets and blood plasma
Systolic pressure is produced when the 2. Blood plasma
ventricle pumps blood out from the heart to
the whole body. Blood coming out flows with 3. Blood group of
high pressure. Diastolic pressure on the other Blood group of recipient
hand is produced when blood flows into the donor
heart. Blood flows with lower pressure. A B AB O

Experiment 3.1 (p. 92) A ××
Questions B×
1. The more active the activity, the higher AB ×

the pulse rate. O ×× ×
2. The rate of intake of oxygen and release
4. (a) To save lives
of carbon dioxide by body cells increases (b) Leukaemia, haemophilia
while carrying out active activity. This
causes the heart to beat more frequently 5. (a) A person of blood group O can
and increases the pulse rate to transport donate blood to any individual
oxygen and carbon dioxide more efficiently. because the person has no A antigen
and B antigen.
Formative Practice 3.2 (p. 95)
1. Blood circulatory system is a special (b) A person of blood group AB can
receive blood from any individual
transport system in complex organisms because his plasma does not contain
which functions to transport nutrients, antibody Anti-A or Anti-B.
respiratory gases and waste products.
(c) Blood bank is the place where blood
8 is stored and retrieved.

6. (a) Hospitals, National Blood Centre
(b) Road accidents, war

7. (a) Blood group AB
(b) Presence of virus and other
unwanted substances
(c) Prevents clotting of blood

Activity 3.8 (p. 110) Summative Practice 3 (pp. 116 – 120)
Questions 1. (a) PULSE
1. The eosin solution stains to form a
(b) TRANSPIRATION
specific pattern in the leaves, stem and (c) CAPILLARY
roots of the plant. (d) PHLOEM
2. Xylem (e) HEART
3. Passage of water in plants is through a (f) ANTIGEN
transport tissue, namely xylem. 2. (a)

Activity 3.9 (p. 111) (b) ×
Questions (c) ×
1. (d) ×

Part that is swollen 3. (a) Valve
(b) Transport oxygenated blood
Part that is shrivelled (c) (i) Blood vessel Q has thick walls to
withstand high blood pressure.
2. Passage of food in plants is through the (ii) Blood vessel R has walls which
phloem. are one cell thick to increase
the efficiency of exchange of
Formative Practice 3.4 (p. 112) substances between blood and
1. Transpiration is a process of loss of body cells through diffusion.

water in the form of water vapour from 4. (a) Oxygen, carbon dioxide, water,
the surface of plants to the air through digested food, waste products
evaporation.
2. (a) vapour, liquid (b) Oxygen, carbon dioxide, water
(b) xylem, phloem (c) During the day, plant cells carry out
3. Light intensity, air humidity, temperature,
air movement photosynthesis and produce oxygen.
4. Passage of water in xylem can be Hence, plant cells do not need
detected with the use of dye because oxygen supply.
water is colourless. 5. (a) (i) dub
5. P: Phloem (ii) lub
Q: Xylem (iii) systolic
R: Xylem (iv) diastolic
S: Phloem (b) Systolic pressure reading is higher
T: Xylem than diastolic pressure reading.
U: Phloem Systolic pressure reading is reading
of blood pressure which is higher
Formative Practice 3.5 (p. 113) when heart ventricle contracts to
1. Similarity: – Both are transport systems force blood out of the heart to be
distributed to the whole body.
– Both transport water, Diastolic pressure reading is reading
nutrients and dissolved of blood pressure which is lower
substances when heart ventricle slackens to
facilitate blood flowing from the whole
– Both exist in complex body back to the heart.
organisms 6. (a) (i) Eric, Roy
(ii) Blood will coagulate.The victim
Difference: Pick one of the differences
shown in Figure 3.31. may die.
(b) (i) Individual 2.
2. Organisms cannot continue to live if they
do not have a unique circulatory system This is because she fulfils the
according to their respective needs. age condition of 18 years and
above but less than 60 years.
She also fulfils the body mass

9

condition of more than 45 kg. CHAPTER 4 Reactivity of Metals
(ii) Pregnant women are not suitable
Brain Teaser (p. 126)
to donate blood. Mineralogists usually use the name bauxite,
7. (a) Transports food civilians such as mine workers use the name
aluminium ore and scientists use the name
(b) Xylem or Y aluminium oxide.
(c) (i) The part above the ring will
Activity 4.1 (pp. 126, 127)
become swollen. Food collected Questions
here cannot be transported to the 1. Carbon dioxide
part below the ring because of 2. Flow the gas through limewater. If the
the absence of X (phloem).
(ii) The plant will dry up and die. limewater turns cloudy, the gas is carbon
dioxide. On the other hand, if the
8. Set A = 54 g = 0.3 g/min limewater does not turn cloudy, the
180 mins gas is not carbon dioxide.
3. (a) Carbon dioxide
Set B = 36 g = 0.2 g/min (b) Carbon dioxide
180 mins 4. (a) calcium chloride + carbon dioxide +

9. (a) Badrul. He has the highest pulse rate water
immediately after activity. (b) calcium oxide + carbon dioxide
5. Calcium, carbon, oxygen
(b) Azizah. Her pulse rate returns to its
original rate after a time interval of 15 Formative Practice 4.1 (p. 128)
minutes after activity. 1. Minerals are naturally occurring solid

10. (a) Location B. elements or compounds with definite
Location A is not suitable for the crystalline structures and chemical
growth of herbs. This is because of compositions.
the absence of light needed by herbs 2. (a) Gold, silver, diamond or other mineral
to carry out photosynthesis.
Location C is not suitable for the elements (Any one)
growth of herbs. High temperature in (b) Bauxite, hematite, galena, cassiterite,
this location will increase the rate of
transpiration of the herbs. quartz or other natural mineral
Location B is suitable for the growth compounds (Any one)
of herbs. Temperature in this dim 3. Calcium oxide that has properties of a
location is able to maintain the rate base is used to neutralise acidic soil.
of transpiration of the herbs. In Silicon dioxide that has a high melting
addition, the presence of sunlight in point is used to make glass laboratory
the bright location enables the herbs apparatus.
to carry out photosynthesis.
Activity 4.3 (pp. 130, 131)
(b) Example of constructed model Questions
1. (a) Magnesium oxide
Transparent umbrella which
can reduce the intensity of (b) Aluminium oxide
light that enters (c) Zinc oxide
(d) Iron oxide
Tissue (e) Lead oxide
2. The more reactive the metal towards
Water oxygen, the more vigorous the reaction.
Device to regulate air humidity 3. Magnesium → Aluminium → Zinc → Iron
→ Lead
10
Brain Teaser (p. 132)
Carbon + oxygen → carbon dioxide
Hydrogen + oxygen → water

Activity 4.4 (pp. 132, 133) (b) Air pollution. Air pollution can be
Questions avoided by filtering the gases
1. (a) Zinc + Carbon dioxide produced before releasing them to
the atmosphere.
(b) No change
(c) Lead + Carbon dioxide Summative Practice 4 (pp. 143 – 145)
2. Zinc and lead. 1. (a) Elements: Iron, Silver, Potassium,
Oxides of metals which are less reactive
than carbon will turn into the metals Tin
when heated with carbon. Compounds: Quartz, Bauxite,
3. Aluminium Galena, Hematite, Limestone
Increasing Carbon (b) Bauxite, Aluminium and oxygen
reactivity Zinc 2. (a) Tin(IV) oxide
(b) Carbon
Lead (c) Tin + oxygen → Tin(IV) oxide
3. (b)
4. Metal extraction. Metals which are less (c)
reactive than carbon in the reactivity 4. (a) Oxygen
series of metals can be extracted from (b) Potassium and sodium are very
their ores through the reduction of the reactive metals. Paraffin prevents
oxide of these metals by carbon. potassium and sodium from reacting
with oxygen and water vapour in the
5. (a) more air.
(b) less 5. (a) Oxygen
(b) To provide oxygen for the reaction.
Formative Practice 4.2 (p. 136) (c) Heat the powdered metal until it
1. The reactivity series of metals is an glows before heating potassium
manganate(VII) to provide oxygen for
arrangement of metals according to their the reaction.
reactivity towards oxygen. (d) To construct a reactivity series of
2. (a) Yes. Metal X is reactive towards metals.
6. For metals which are more reactive
oxygen because metal X burns with a than carbon, extraction of the metals
bright flame. is through the electrolysis method. For
(b) Metal Y is less reactive than metal X. metals which are less reactive than
carbon, extraction of the metals is
(c) X through reaction of the metal ores with
Y carbon.
Z 7.

3. (a) oxygen Mixture of iron Bottle/Plastic bag
(b) potassium powder, limestone
(c) extraction powder and coke

4. (a) Potassium Air at room Drinking
(b) Gold temperature straw

5. (a) Carbon and hydrogen Air at room
(b) Carbon and hydrogen can react with
oxygen. Fan Hot air Cooking oil Hot temperature
blade air
Formative Practice 4.3 (p. 141)
1. (a) Electrolysis Motor

(b) Reduction of iron ore with carbon Motor Water
2. (a) Tin
Paper clip
(b) (i) Iron ore, limestone, coke
(ii) Hot air

(c) (i) Slag
(ii) Molten iron

3. (a) Soil erosion. Problem of soil erosion
can be solved by replanting trees.

11

Explanation: Represent – Reaction between sodium hydrogen
Substance Blast furnace carbonate and hydrochloric acid
Slag
Bottle Molten iron 6. (a) Wrapping the polystyrene cup with
Cooking oil Heating device cotton wool or felt cloth, using a lid
Water Iron ore for the cup.
Motor Limestone
Iron powder (b) Heat insulators such as cotton
Limestone powder wool and felt cloth and lid for cup
reduces the transfer of heat to the
Innovative step: Fan blade is connected surroundings.
in a direction opposite
to the normal direction Formative Practice 5.1 (p. 154)
so that sucked air flows 1. (a) An endothermic reaction is a
through the motor to be
heated. Motor is also chemical reaction that absorbs heat
cooled by this flow of from the surroundings.
air. (b) An exothermic reaction is a chemical
reaction that releases heat into the
CHAPTER 5 Thermochemistry surroundings.
2. Thermochemistry is the study of heat
Experiment 5.1 (pp. 149 – 151) changes when chemical reactions occur.
Questions (p. 151) 3. The rate of respiration increases when
1. (a) Release of heat is shown by the rise performing vigorous physical activities,
because respiration is an exothermic
in thermometer reading. reaction. Heat produced by the exothermic
(b) Absorption of heat is shown by the reaction is absorbed into the body. Hence,
the body temperature increases.
drop in thermometer reading. 4. (a) Global warming
2. (a) Thermal equilibrium (b) Reduce burning of fossil fuels.
5. (a) Exothermic reaction.
(b) When the net rate of heat transfer (b) Exothermic reactions release heat
between the products of reaction into the surroundings and increase
and thermometer is zero, products the temperature. High temperatures
of reaction and thermometer is can relieve muscle cramp.
in thermal equilibrium. Hence,
the temperature reading on the Summative Practice 5 (pp. 155 – 158)
thermometer is fixed at maximum 1. (a) Exothermic reaction
value or minimum value.
(b) Endothermic reaction
3. (a) The temperature during reaction is (c) Exothermic reaction
higher than the temperature before (d) Endothermic reaction
reaction occurred. (e) Exothermic reaction
(f) Exothermic reaction
(b) The temperature during reaction is 2. (a) released
lower than the temperature before (b) increases
reaction occurred. (c) hot
(d) absorbed
4. – Sodium hydroxide dissolving in water 3. (a) THERMOCHEMISTRY
– Reaction between sodium hydroxide (b) PHOTOSYNTHESIS
and hydrochloric acid (Neutralisation) (c) RESPIRATION
(d) THERMOMETER
5. – Ammonium chloride salt dissolving in (e) ENDOTHERMIC
water (f) EXOTHERMIC

12